The invention relates to a lock for non-rotatingly and axially securing a coupling sleeve of a power take off shaft, especially of a self driving implement, e.g. a tractor.
The coupling sleeves include a bore with multiple splines and the power take off shaft has a corresponding multiple spline profile with a continuous annular groove. The coupling sleeve has a second bore to receive a locking element. The second bore is arranged at right angles relative to the longitudinal axis of the first bore. The second bore intersects the annular groove and with the locking element provided in the second bore, the locking element engages the annular groove via at least one locking face. This locking establishes a non-releasable connection between the power take off shaft and the coupling sleeve.
It is known to secure coupling sleeves and power take off shafts via locking elements in the form of balls which are guided in radial apertures of the coupling sleeve. These balls are secured radially by a locking ring and enter the locking position by engaging an annular groove extending transversely relative to the power take off shaft axis. Such locks are intended to be used as high speed locks, which is why they are provided with play in both the axial and the torque transmitting directions. If such locks are implemented in a connection subject to vibration in the direction of rotation and/or in the axial direction, deflection of the toothed profile or the locking elements may result.
DE 3340130 C1 proposes an embodiment comprising a pivotable locking ring and a locking bolt. The locking bolt presses against a wedge additionally provided in the coupling sleeve. The wedge is intended to balance the play, in the circumferential direction between the teeth of the coupling sleeve and those of the wheel shaft
U.S. Pat. No. 4,645,368 discloses a high speed locking mechanism consisting of a locking pin engaged in a bore, transversely positioned relative to the power take off shaft axis. The bore is positioned at a desired radial distance and is at the level of the annular groove. The locking pin is spring loaded and guided in the bore. The locking pin projects from a radially stepped end of the bore, the locking pin projects from this bore so that it may be displaced inwardly from the outside by applying force against the force of the spring. The locking pin engages the shaft annular groove via a thickened portion and connects the coupling sleeve with the power take off shaft. The pin is released by pushing in the locking pin.
Both of the above designs of a shaft and sleeve connection are intended for high speed assembly and have play in both the axial and torque transmitting directions. In the case of the latter design, the force locking connection is achieved exclusively through the force of the spring.